1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * linux/fs/affs/dir.c |
4 | * |
5 | * (c) 1996 Hans-Joachim Widmaier - Rewritten |
6 | * |
7 | * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem. |
8 | * |
9 | * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. |
10 | * |
11 | * (C) 1991 Linus Torvalds - minix filesystem |
12 | * |
13 | * affs directory handling functions |
14 | * |
15 | */ |
16 | |
17 | #include <linux/iversion.h> |
18 | #include "affs.h" |
19 | |
20 | static int affs_readdir(struct file *, struct dir_context *); |
21 | |
22 | const struct file_operations affs_dir_operations = { |
23 | .read = generic_read_dir, |
24 | .llseek = generic_file_llseek, |
25 | .iterate_shared = affs_readdir, |
26 | .fsync = affs_file_fsync, |
27 | }; |
28 | |
29 | /* |
30 | * directories can handle most operations... |
31 | */ |
32 | const struct inode_operations affs_dir_inode_operations = { |
33 | .create = affs_create, |
34 | .lookup = affs_lookup, |
35 | .link = affs_link, |
36 | .unlink = affs_unlink, |
37 | .symlink = affs_symlink, |
38 | .mkdir = affs_mkdir, |
39 | .rmdir = affs_rmdir, |
40 | .rename = affs_rename2, |
41 | .setattr = affs_notify_change, |
42 | }; |
43 | |
44 | static int |
45 | affs_readdir(struct file *file, struct dir_context *ctx) |
46 | { |
47 | struct inode *inode = file_inode(f: file); |
48 | struct super_block *sb = inode->i_sb; |
49 | struct buffer_head *dir_bh = NULL; |
50 | struct buffer_head *fh_bh = NULL; |
51 | unsigned char *name; |
52 | int namelen; |
53 | u32 i; |
54 | int hash_pos; |
55 | int chain_pos; |
56 | u32 ino; |
57 | int error = 0; |
58 | |
59 | pr_debug("%s(ino=%lu,f_pos=%llx)\n" , __func__, inode->i_ino, ctx->pos); |
60 | |
61 | if (ctx->pos < 2) { |
62 | file->private_data = (void *)0; |
63 | if (!dir_emit_dots(file, ctx)) |
64 | return 0; |
65 | } |
66 | |
67 | affs_lock_dir(inode); |
68 | chain_pos = (ctx->pos - 2) & 0xffff; |
69 | hash_pos = (ctx->pos - 2) >> 16; |
70 | if (chain_pos == 0xffff) { |
71 | affs_warning(sb, function: "readdir" , fmt: "More than 65535 entries in chain" ); |
72 | chain_pos = 0; |
73 | hash_pos++; |
74 | ctx->pos = ((hash_pos << 16) | chain_pos) + 2; |
75 | } |
76 | dir_bh = affs_bread(sb, block: inode->i_ino); |
77 | if (!dir_bh) |
78 | goto out_unlock_dir; |
79 | |
80 | /* If the directory hasn't changed since the last call to readdir(), |
81 | * we can jump directly to where we left off. |
82 | */ |
83 | ino = (u32)(long)file->private_data; |
84 | if (ino && inode_eq_iversion(inode, old: file->f_version)) { |
85 | pr_debug("readdir() left off=%d\n" , ino); |
86 | goto inside; |
87 | } |
88 | |
89 | ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); |
90 | for (i = 0; ino && i < chain_pos; i++) { |
91 | fh_bh = affs_bread(sb, block: ino); |
92 | if (!fh_bh) { |
93 | affs_error(sb, function: "readdir" ,fmt: "Cannot read block %d" , i); |
94 | error = -EIO; |
95 | goto out_brelse_dir; |
96 | } |
97 | ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); |
98 | affs_brelse(bh: fh_bh); |
99 | fh_bh = NULL; |
100 | } |
101 | if (ino) |
102 | goto inside; |
103 | hash_pos++; |
104 | |
105 | for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) { |
106 | ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); |
107 | if (!ino) |
108 | continue; |
109 | ctx->pos = (hash_pos << 16) + 2; |
110 | inside: |
111 | do { |
112 | fh_bh = affs_bread(sb, block: ino); |
113 | if (!fh_bh) { |
114 | affs_error(sb, function: "readdir" , |
115 | fmt: "Cannot read block %d" , ino); |
116 | break; |
117 | } |
118 | |
119 | namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], |
120 | (u8)AFFSNAMEMAX); |
121 | name = AFFS_TAIL(sb, fh_bh)->name + 1; |
122 | pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n" , |
123 | namelen, name, ino, hash_pos, ctx->pos); |
124 | |
125 | if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN)) |
126 | goto done; |
127 | ctx->pos++; |
128 | ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); |
129 | affs_brelse(bh: fh_bh); |
130 | fh_bh = NULL; |
131 | } while (ino); |
132 | } |
133 | done: |
134 | file->f_version = inode_query_iversion(inode); |
135 | file->private_data = (void *)(long)ino; |
136 | affs_brelse(bh: fh_bh); |
137 | |
138 | out_brelse_dir: |
139 | affs_brelse(bh: dir_bh); |
140 | |
141 | out_unlock_dir: |
142 | affs_unlock_dir(inode); |
143 | return error; |
144 | } |
145 | |